The field bees returning to their old location and finding an empty box (even one with foundation or combs) might join a nearby queenright colony, if one is very near their old location, especially during a strong to moderate honey flow. That's what mine do, a cluster may form at the old location, but since there are several other colonies nearby the clusters are usually absorbed by the next morning.
If you screen them in the night before it should be easier to ensure they all stay together.